Manufacture of glycols.



"tJ'NllTED s'ra'rns Parana c ar on.

CORPORATION OF TEXAS.

MANUFACTURE OF GLYCOLS.

Patented Feb. 113, 11911 '3.

I ,2 5,903. Specification of Letters Patent. No Drawing.

To all whom it may concern:

Be it known that we BENJAMIN 'l. BROOKS and Inwnv I-IUMrnnnY, bothcitizens of the United States, residing in Pittsburgh, Allegheny county,State of Pennsylvania, have invented certain new and useful improvementsin the Manufacture of (llycols; and we do hereby declare the followingto be a full, clear, and exact description of the invention, such asWill enable ol hers skilled in the art to which it apportains to makeand use the same.

This invention relates to the production of glycols or mixturesoiglycols from dichlorinated hydrocarbons of the ethylene series ormixtures thereof...

The dichlorinated hydrocarbons which are used for the production of theglycols, according to the present invention, may be the individualdichlorinated hydrocarbons such as ethylene dichlorid or Dutch liquor,or similar chlorids. The mixture of dichlorids which is produced fromthe unsaturated hydrocarbons of oil gas is of particular value in thisprocess fol-the reason that it can be readily prepared from the oil gasby inexpensive methods and for the further reason that it permits theproduction therefrom by a single process of a mixture of glycols adaptedfor use to advantage directly as a mixture or for the productiontherefrom of the individual glycols.

()il gas, when suitably produced, is rich in olefins, and particularlyin olelins of the ethylene series. The average oil gas may thus havefrom 33 to.43% of olefins, the remainder of the gas being of hydrogenand saturated hydrocarbons iii varying proportions. The olefins orunsaturated hydrocarbons of the oil gas consist principally of ethyleneand propylene, but small amounts of other hydrocarbons such as butylene,amylene, benzol, etc., may also be present. The relative proportions ofethylene and propylene will also vary with different oil. gasesdepending upon the method of production of the gas, the material fromWhich produced, etc. The relative amounts of ethylene and propylene canalso be varied and to a certain extent regulated by the methodApplication filed March 23, 1916. Serial No. 86,063.

of producing the oil the product obtained be correspondi n gl yunsaturated hydrocarbons from which the dichlorids are produced, theproduction of the oil gas and of the dichlorids therefrom can beeffected in any suitable manner. It will be understood by those skilledin the art that various methods of producing the oil gas and ofchlorinating the gas to produce the dichlorids are available for thesepurposes.

According to the present invention, the dichlorinated hydrocarbons ofthe ethylene series, separately or in admixture With each other, arecaused to react with an alkali formate in the presence of an organicsolvent such as methyl alcohol. The reaction of the dichlorinatedhydrocarbon and the alkali form-ate results in the production of theformyl derivative or fol-mate of the corresponding hydrocarbon orhydrocarbons, alkali chlorid being at the same time set free. Theformatesthus formed are acted upon by the methyl alcohol to give thecorresponding glycol or glycols and methyl formate.

It has been heretofore proposed to produce glycols by conversion of thechlorids into acetates and recovery of the glycols from the diacetates.This process, however, requires expensive apparatus, a silver liningbeing commonly used to resist the glacial acetic acid utilized. Theacetate method is, moreover, one in which small yields of the glycol areobtained, for example, yields of about 35% of the theoretical.

The novel method 01 the. present invention can be practised in simpleand inexpensive apparatus and with yields as high as 80% or higher. Suchyields are much higher than could a prion be expected, from analogousprocesses of the prior art.

A mixture of the dichlcrids such as is obtained from oil gas is heatedwith a slight excess (say 1 to 2 times the theoretical) of the alkaliformate. We consider sodium formate better than the potassium for-matefor the reason that it is not hygroscopic and is cheaper and more easilyobtained. An excess of say threeto five volumes of methyl alcohol isalso added, and the resulting mixture is heated in an autoclave to atemperature of about 180 C. and under a maximum pressure of about 260lbs. for about five or six hours. The pressure may be generated withinthe autoclave by heating to the temperature indicated. If thus theautoclave is two-thirds full, the pressure will attain a value of, forexample, 200 to 260.1bs. temperature of the heating may be variedsomewhat, for example, between 140 C. to 200 C.; and the pressure canalso bevaried, for example, between 100 lbs. and 260 lbs.

The reaction is promoted by stirring or agitating the contents of theautoclave, and this agitation can, in practice, be obtained, forexample, by rotating the autoclave.

It will be noted that the process is easily carried out in simpleapparatus and with methyl alcohol as the solvent and as one of thereagents taking part in the operation. The process is thus much moreadvantageous than the acetate method, both in its method of procedureand in the increased results obtained.

After the operation is completed, the liquid contents are separated fromany salt formed, by filtration, able manner, and the liquid mixture isthen subjected to fractional distillation to recover therefrom thedifferent constituents. The excess of methyl alcohol and the methylformate are first removed and can be recovered for reuse or for furthertreatment. The glycols, having higher boiling points, are preferablydistilled in cacao in order to avoid decomposition. Higher temperatures,such as would cause decomposition, are similarly avoided during the mainreaction, for the same reason.

Where a mixture of glycols is obtained, as is the case where a mixtureof dichlorinated hydrocarbons such as are obtained from oil gas is usedas the starting material, this mixture can be directly used or it can befurther fractionated and the separate glycols- (ethyleneglycol,propylene glycol, etc.,) recovered therefrom.

The methyl formate resulting from the rocess can be subjected to asuitable saponilication with caustic alkali and the alkali The or in anyother suit- It "will thus be seen that the process is one of notableeconom in that expensive reagents are not re uired and inthat'the'alkali formate and t e methyl alcohol are to a greater or lessextent recovered ina form suitable for re-use.

As abovepointed out, the mixture of die chlorinated hydrocarbonsobtained from oil gas is of particular value in the practice of theinvention for the reaso amo others, that the resulting mixture 0 glycois produced directly and is available for use as such or as a source ofthe individual glycols.

When amixture of the dichlorina ed hydrocarbons is thus-used, theformation of the different gl cols proceeds smoothly and simultaneouswith the resulting production of the glyco mixture.

Whatwe claim is:

l. The method of producing glycols. from dichlorinated ethylenehydrocarbons which comprises subjecting such hydrocarbons'to reactionwith an alkali formats in the presence of an alcohol; substantially asdescribed. -2. The method of producing glycols from dichlorinatedethylene hydrocarbons, which comprises heating the same under pressurewith an alkali formate and an alcohol; substantially as described.

3. The method of producing glycols from dichlorinated ethylenehydrocarbons, which comprises heating the same to a temperature of about140 to 200 C. and a'presure of 100 to 260 lbs. together with an alkaliformate and an alcohol; substantially 'as described.

4. The method of producin lycols from dichlorinatecLethylene hydrocasicomprises subjecting the same to the action of sodium formate and methylalcohol; substantially-as described. I

5. The method of producing lycols from dichlorinated ethylenehydrocafiions, which comprises heating the same to a'high temperatureand pressure in the presence of sodium formate and methyl alcohol;substantially as described. 4

6. The method of producing a' mixture of glycols from a mixture ofdichlorinated ethylene hydrocarbons, which comprises subjecting themixture of dichlorinated hydrocarbons to reaction with an alkali formateand an alcohol; substantially as described.

7. The method of converting dichlorinated hydrocarbons into diformates,which comprises heating the same with alkali format'es in the presenceof an organic solvent; substantially as described.

8. The method of converting diform l derivatives of hydrocarbons intoglyco ons, which 9. The method of producing glycols from ering thealkali formate for further use; dichlorinated hydrocarbons, whichcomsubstantially as described. prises subjecting the dichlorinatedhydro- In testimony whereof we our signa- 10 carbons to reaction with analkali formate tures. and an alcohol and thereby producing the glycolsand the formate of the alcohol, and BENJAMIN BROOKS. saponifying theformate and thereby recov- IRWIN i I i 2': a

